FR2786819A1 - RADIAL PISTON PUMP - Google Patents

Abstract

Pump providing high pressure fuel in common rail type fuel injection systems for internal combustion engine. The installation comprises a pump body (7, 8) with a drive shaft having an eccentric segment against which the pistons housed in respective holes are supported and which perform the reciprocating movements in the holes under the effect of the drive shaft. An axial bearing washer (13) with several peripheral nozzles (18) penetrates into corresponding grooves of the pump body (7). Using a fixing installation (15, 16), it is blocked in the pump body (7, 8).

Description

State of the art

  The present invention relates to a piston pump

  radial tones for supplying fuel at high pressure in internal combustion engine fuel injection systems, in particular common rail injection systems comprising an engine shaft mounted in a pump body, this

  tree with an eccentric segment on which pre-

  several pistons each housed in an ele-

  respective, radial with respect to the motor shaft, these pistons reciprocating during rotation

  of the drive shaft in the basic bore respec-

  tif. Such a radial piston pump is for example known from the document DE 42 16 877. The drive of the

  radial piston pump means that when using pi-

  toothed pins with inclined teeth, forces are encountered

  axial than axial bearing washers provided with a ma-

  plain bearing must absorb. The bearing washer

  axial is centered in the housing and can be locked in rotation

  tation by two peripheral nozzles coming to take in

  grooves in the pump body. Following the principle of

  tage, it may happen that half of the pump body must be mounted upside down with the installation of an axial bearing washer. In this case, it is necessary to block the axial bearing washer to prevent it from being ejected from its centered position. The axial bearing washer can be locked, for example, using one or more bosses.

  The realization of one or more bosses required

  site, however, an additional assembly work stage

  to hush up. In addition, additional accessory devices are required. In addition, there is the risk that the washer

  axial bearing is damaged by the production of bosses

  ges. The present invention aims to develop means for locking an axial bearing washer

  in a pump body to simplify assembly.

  The invention proposes in particular to avoid

  damage to the axial bearing washer during assembly.

  To this end, the invention relates to a radial piston pump of the type defined above, characterized in that an axial bearing washer or a starting ring has several spouts distributed at the periphery, coming to take in corresponding cutouts of the body. pump, and by which the fixing installation is mounted in

the pump body.

  A particularly advantageous embodiment

  geux of the invention is characterized by an annular groove

  produced in the pump body, this groove serving to

  have a fixing ring forming the fixing installation

  tion, this ring having projecting parts, in the form of

  clips surrounding the spouts of the fixing ring.

  The annular groove is used to lock the fixing ring in the pump body. The fixing ring can

  either be closed or split like an elastic ring.

  According to another particular characteristic-

  interesting of the invention, the fixing installation is formed by several stirrups surrounding the spouts and whose curved ends are respectively engaged in corresponding holes in the pump housing In the assembled state, the stirrups surround the spouts and hold them securely in the pump body. In

  In principle, a stirrup would suffice to ensure this. Of my-

  Preferably, two or more stirrups are nevertheless used. It is clear that it is necessary to have as many beaks as

  stirrups or clamp-like projections.

  According to another particularly embodiment

  advantageous the curved ends of the stirrups have an au-

  be distance between them as the respective holes of the pump body. Thus the curved ends of the stirrup are prestressed in the assembled state. This prevents the caliper from sliding out of the pump housing after

its mounting.

  According to a particularly embodiment

  advantageous the fixing installation is formed by a round

  delle of fixing of which the periphery comprises several grif-

  curved blades which can catch on the pump body when the axial bearing washer is mounted between the round

  mounting plate and pump body. In this mode of rea-

  In addition, it is possible that the axial bearing washer has a particular external shape, for example a hexagon or eight-hexagonal shape. The number of claws of the fixing disc can be adapted to the number of spouts of the

axial bearing washer.

  According to another particularly advantageous characteristic of the invention, an annular groove is produced in the pump body, a groove in which the curved claws come to take relative to the fixing washer. Instead, one can also perform

  cavities in the pump body. The annular groove pre-

  nevertheless feels the advantage of simplifying the mounting of the disc

of fixation.

  According to another advantageous characteristic of the invention, the fixing installation is formed in a

  elastic material, in particular a spring steel.

  This embodiment has the advantage of being able to simply clip the fixing device onto the pump body. This means that the axial bearing washer and the mounting installation can be mounted manually without the need for any tools. In addition, mounting can be automated to allow

  assembling large series in a short time.

  According to another particularly advantageous characteristic of the invention, the axial bearing washer

  comprises in cavities several lubrication grooves directed radially. The lubrication grooves in the axial bearing washer allow the lubrication agent to pass from the pump body to the bearing circulation surface.

  According to another particular characteristic-

  advantageously the internal diameter of the pump body at the level of the fixing installations is chosen to avoid any loosening of the fixing installation. This means in detail that one avoids

  any exhaust from protrusions in the form of clamps or grif-

  fes out of the annular groove or the stirrup out of the holes; this somehow means that the installation of

fixing is self-locking.

  The present invention will be described below in more detail with the aid of the appended drawings, in which: * FIG. 1 shows an axial section of a radial piston pump, * FIG. 2 is a detail view on a scale enlarged in Figure 1 corresponding to a first embodiment of the invention, * Figure 3 is a sectional view along line III-III of Figure 2, * Figure 4 is a detail view on a scale enlarged according to FIG. 1 corresponding to a second embodiment of the present invention, * FIG. 5 is a sectional view along the line VV of FIG. 4,

  * Figure 6 shows an enlarged detail of the figure

  gure 1 corresponding to a third embodiment of the invention, * FIG. 7 is a view along the section of line VII- VII of FIG. 6, * FIG. 8 is a sectional view of an embodiment with a starter ring,

  * Figure 9 shows another embodiment of a round

  delle axial bearing, * Figure 10 shows an embodiment of a starting ring. The radial piston pump shown in section in FIG. 1 is used in particular in common rail injection systems for supplying fuel to diesel engines. The expression "common rail" is synonymous with common driving. Unlike current high pressure injection systems in which fuel is supplied

  the different combustion chambers by separate pipes

  trimmed, the injectors of the ramp injection systems

  mune are supplied from a common pipe.

  The radial piston pump generally having the reference 1 in FIG. 1, comprises a motor shaft 2 mounted in a pump body 7, 8; this tree has an eccentric segment 3. The eccentric shaft segment 3 carries a ring 9 which can rotate relative to the eccentric segment 3. The ring 9 comprises three flats offset by 120 on which a piston is supported; in the sectional view of Figure 1 appears only one piston 4. The piston 4 is housed in an elementary bore 5 in a radial direction relative to the motor shaft 2 to perform a reciprocating movement;

  this piston defines a cylinder chamber 6.

  The radial piston pump 1 shown in FIG.

  gure 1 allows to put at high pressure the fuel supplied by an upstream pump from a tank. Fuel to

  high pressure is then delivered into the common pipe evo-

  quée above. During the transfer stroke, the pistons 4 are moved by the eccentric movement of the ring 9 relative to the axis of the drive shaft 2. In the suction stroke, the pistons 4 move, supported by a spring 10 towards the axis of the drive shaft

  to draw fuel into the cylinder chambers 6.

  The motor shaft 2 is slidably mounted both in the radial direction and in the direction

  axial of the pump body 8 by flange sockets 11, 12.

  Axial mounting is ensured by axial bearing washers

13, 14.

  As shown in the enlarged detail of Figure 2, the axial bearing washer 13 is held in place after assembly and before the installation of the sleeve 11 and the drive shaft 2, using a ring of

  attachment 15. Two projecting parts 16, 17 in the form of a pin-

  these are made on the fixing ring 15; among this-

  these, the detail of figure 2 shows only the part in

projection 16.

  The section view III-III of Figure 3 shows

  only the axial bearing washer 13, the housing part

  tier 7 and the fixing ring 15 for the purpose of simplification

  tion. According to Figure 3, the axial bearing washer 13 carries two spouts 18, 19. The spouts 18, 19 are surrounded by protrusions 16, 17 in the form of clamps formed on the fixing ring 15. In addition, Figure 3 shows that the ring of

attachment 15 is split in point 20.

  Figure 2 shows that the housing part 7 has an annular groove 21. The annular groove 21

  is used to receive the fixing ring 15. During assembly,

  simply securing the fixing ring 15 in an elastic manner in the annular groove 21. The protrusions 16 and 17 in the form of clamps which surround the nozzles 18, 19 ensure the holding of

  the fixing ring 15 relative to the housing part 7.

  In the second embodiment of the invention shown in Figure 4, the axial bearing washer 13 is locked using a stirrup 24. The ends 25, 26 of the stirrup 24 are engaged in bores 27 , 28 produced in the housing part 7. As best appears in the sectional view of FIG. 5, the stirrup 24 surrounds the spout 18 of the axial bearing washer 13. The number of spouts

  18, 19 of the axial bearing washer 13 is variable. Any-

  times, there are at least two spouts to guarantee the holding of the

axial bearing washer 13.

  In the third embodiment of

  the invention shown in Figures 6, 7, the washer of pa-

  axial link 13 is held on the housing part 7 by a fixing washer 30. The axial bearing washer 13 is

  mounted between the housing part 7 and the fixing washer

  tion 30. The washer 30 carries several claws 31, 32, 33,

  34. The claws 31-34 are curved with respect to the round

  delle 30. As it appears in figure 6, the claw 33 pe-

  Neter in an annular groove 35 made in the housing part 7. The same remark applies to the other claws distributed regularly at the periphery of the fixing washer.

  As shown in Figures 2, 4, 6, the dis-

  tance 40 between the housing parts 7, 8 is so weak

  ble that this certainly allows the mounting of the fixing installations but avoids during operation any loosening of the fixing installations. Fixing installations

  shown in Figures 2 to 7 are made of stainless steel

  elastic, flexible spell. Alternatively, it is also possible to use

  use plastics with the same properties.

  According to Figures 3, 5, 7, the axial bearing washer 13 has lubrication grooves 36, 37, 38, 39 allowing the passage of the lubricating agent from the inside of the bearing to the sliding surface of the axial bearing . In the embodiment of FIG. 8 of the invention, instead of an axial bearing washer, a launch ring 41 is used. The launch or start ring 41 is held in place using 'a stirrup 24. Figure 9 shows an axial bearing washer 42 on which are made three spouts 43, 44, 45 in the form of semicircles. The asymmetrical arrangement of the spouts 43-45 guarantees the correct mounting of the axial bearing washer 42. FIG. 10 shows the starting ring 47 with two spouts 48, 49 in the form of semicircles. Three flats 50, 51, 52 guarantee with the spouts 48, 49, the correct mounting

starting ring 47.

RE VE N D I C A T I ON S

  1) Radial piston pump for supplying fuel at high pressure in internal combustion engine fuel injection systems, in particular common rail injection systems comprising an engine shaft (2) mounted in a

  pump body (7, 8), this shaft having a segment (3) extending

  very on which preferably rely several pistons (4)

  each housed in a respective elementary bore (5),

  dial with respect to the drive shaft (2), these pistons reciprocating during the rotation of the drive shaft (2) in the respective elementary bore (5), characterized in that an axial bearing washer (13) or a starter ring

  (41) has several spouts (18, 19) distributed around the periphery

  laughs, coming to take in corresponding cuts of the

  pump body (7), and by which the installation of

  tion (15, 24, 30) is mounted in the pump body (7, 8).

  2) radial piston pump according to claim 1, characterized by an annular groove (21) formed in the pump body (7), this groove serving to receive a fixing ring (15) forming the fixing installation, this ring having

  protruding parts (16, 17) in the form of clips which surround

  rent the spouts (18, 19) of the fixing ring (15).

  3) Radial piston pump according to claim 1, characterized in that the fixing installation is formed by several stirrups

  (24) surrounding the spouts (18, 19) and the ends of which

  curved (25, 26) are engaged respectively in per-

  corresponding slots (27, 28) of the pump housing (7).

  4) Radial piston pump according to claim 3, characterized in that the curved ends (25, 26) of the stirrups (24) have a different distance from each other than the respective holes (27,

28) of the pump body (7).

   ) Radial piston pump according to claim 1, characterized in that the fixing installation is formed by a fixing washer (30) whose periphery comprises several claws (31-34), curved, which can catch in the pump body (7) when the axial bearing washer (13) is mounted

  between the fixing washer (30) and the pump body (7).

  6) Radial piston pump according to claim 5, characterized by an annular groove (35) produced in the pump body

  (7), groove in which the claws take hold (31-

  34) bent with respect to the fixing washer (30).

  7) Radial piston pump according to any one of the res-

  dications previous, characterized in that the fixing installation (15, 24, 30) is formed in a

  elastic material, in particular a spring steel.

  8) Radial piston pump according to any one of the resales

  previous indications, characterized in that

  the axial bearing washer (13) has more cavities

  lubrication grooves (36, 39) directed radially.

  9) Radial piston pump according to any one of the res-

  dications preceding, characterized in that the internal diameter of the pump body (8) at the level of the fixing installations (15, 24, 30) is chosen to avoid

  any loosening of the fixing installation (15, 24, 30).